Re: RM and abstract syntax trees

From: David Cressey <cressey73_at_verizon.net>
Date: Thu, 01 Nov 2007 11:44:43 GMT
Message-ID: <L_iWi.16676$gl1.14765@trndny09>

"David BL" <davidbl_at_iinet.net.au> wrote in message news:1193810534.716595.45040_at_t8g2000prg.googlegroups.com...

> I guess I equate pointers with edges in a directed graph (where by
> directed graph I'm referring to the formalised notion of a set of
> nodes plus a set of directed edges between nodes), and naturally I
> regard an AST as an acyclic directed graph.

This is a good working definition. My claim that pointers are really addresses can be recast as a special case of the above.

But the objections concerning data models based on directed graphs turn out to be the same as the objections concerning implementations that rely on (exposed) pointers used as addresses.

Those objections don't mean that the RM is superior to directed graphs in all instances. Reference what Marshall and others said. It does mean that caution is needed when proposing a directed graph model to replace the RM as the most general model. Received on Thu Nov 01 2007 - 06:44:43 CDT